Heat Exchanger (241, 251)
  241     Prior to Serial #209197 Part is NLA.
          From #209197 to #227971 use 7019853.
          From #227972 to #303251 use 7017502.
          Starting with #303252 use 7016733.
  251     Prior to Serial #209197 Part is NLA.
          From #209197 to #227971 use 7019853.
          From #227972 to #299951 use 7017502.
          Starting with #299952 Part is NLA.